遮荫对玉米遗传缺陷性空秆的诱发效果研究

以容易发生空秆和不容易空秆的成对近等基因系、易发生空秆的杂交种、正常杂交种、自交系为试材,采用人工遮荫方法进行光照胁迫,对诱发空秆的光照因子及其胁迫效果进行研究。结果表明,试验初步验证了玉米存在遗传缺陷性空秆现象,弱光胁迫对不同品种均会造成空秆并随着遮荫强度增大而增加,品种间差异很大。抽雄期至吐丝末期是玉米空秆对弱光胁迫的最敏感时期,雌穗不能正常吐丝是造成品种异常性高比率空秆的主因,结穗率降低是次要原因。易空秆近等基因系沈农98A空秆的光胁迫强度应在遮荫38%以下;不空秆近等基因系沈农98B与正常自交系昌7-2的耐荫性相近,诱发其空秆的光胁迫强度范围应在遮荫38%~60%之间;在遮荫75%左右时,东单90、东单80与郑单958之间,空秆率有明显区别。

Inducing Effects of Shade on Genetic Defect Barren Stalk of Maize

Illumination factor inducing barren stalk and its stress effects were studied by the method of artificial shade using paired near-isogenic line of vulnerable and invulnerable barren stalk, hybrids prone to barren stalk and normal hybrid and its inbred line as experimental materials. The trial preliminarily verified that maize had phenomena of genetic defect barren stalk. The results showed that weak illumination stress could cause barren stalk to different varieties and varietal difference increased with the increasing of shading intensity. Abnormal spinning of females spike was the major reason to the high ratio of barren stalk and the secondary reason was the lower setting. The most sensitive period to illumination stress was tasseling stage to late spinning stage. Illumination stress intensity of Shennong98A should be below 38%. Shade tolerance of Shennong98B and Chang7-2 were similar, whose stress intensities should be between 38% and 60%. Rates of barren stalk of Dongdan90, Dongdan80 and Zhendan958 had obvious differences under 75% shading.